We propose to extend our studies of porphyrins and of hemoproteins by x-ray photoelectron spectroscopy (ESCA). In our work on porphyrins we expect to measure a few more core binding energies of particular interest, especially those of reduced porphyrins. We expect to emphasize, however, studies of multiplet splittings and of satellite structure in the ESCA of porphyrins, and to build a source so we can study some porphyrins in the gas phase. These studies will allow us to get more complete charge distributions than can be gotten from work on solids. Work on hemoproteins is restricted to study of metal core levels because the protein contains so many nitrogens. We propose to study core binding energies and 3s multiplet splittings of several compounds of myoglobin, of horseradish peroxidase and of cytochrome c, as well as, perhaps, some other proteins.